This invention relates to the chemical vapor deposition (CVD) of copper thin films, and specifically to a method of adding water during the CVD process in improve the adhesive properties of the copper thin film on metal nitride substrates.
The use of water in CVD of copper is known from Gelatos, et al., xe2x80x9cChemical vapor deposition of copper from Cu+1 precursors in the presence of water vaporxe2x80x9d, Appl. Phys. Lett. 63(20), 1993, pp. 2842-2844, wherein a method of adding water vapor to Cu(hfac)(tmvs), where hfac=hexafluoroacetylaceton and tmvs=trimethylvinylsilane, improves the deposition rate of copper and decrease the resistivity of the deposited copper thin films. Hochberg, et al., disclose a method of adding water to a Cu(hfac)(tmvs) precursor in the form of hexafluoroacetylacetone (hfac) dihydrate (H(hfac)(2H2O), in xe2x80x9cChemical Additives For Improved Copper CVD Processing Using (hfac)Cu(tmvs)xe2x80x9d, Advanced Metallization for ULSI Applications, 1994, wherein the stability of the precursor is improved and the deposition rate of copper thin films are increased, however, the conductivity of the copper thin films is not improved, and the formed copper thin films have a rough texture.
Jain, et al., xe2x80x9cChemical Vapor Deposition of Copper from (hfac)CuL (L=tmvs and 2-butyne) in the Presence of Water, Methanol and Dimethyl Etherxe2x80x9d, Chem. Mater., 8, pp 1119-1127, 1996, disclose a method of adding water vapor to (hfac)Cu(tmvs). The deposition rate of the copper precursor is improved, but the resistivity of the deposited copper is poor.
A method of forming a copper thin film by chemical vapor deposition, includes introducing a wafer into a chemical vapor deposition chamber; humidifying helium gas with water to form a wet helium gas for use as the atmosphere in the chemical vapor deposition chamber; depositing a copper seed layer at a wet helium flow rate of between about 5.0 sccm and 20.0 sccm during a wafer temperature rise from ambient temperature to between about 150xc2x0 C. to 230xc2x0 C.; and depositing a copper thin film layer at a wet helium flow rate of between about 0.2 sccm to 1.0 sccm and at a temperature of between about 150xc2x0 C. to 230xc2x0 C.
An object of the invention is provide an improved copper thin film deposition through the introduction of water into the CVD process.
Another object of the invention is to provide a copper thin film having a low resistivity.
A further object of the invention is to provide a precursor to be used in CVD of copper thin films.
This summary and objectives of the invention are provided to enable quick comprehension of the nature of the invention. A more thorough understanding of the invention may be obtained by reference to the following detailed description of the preferred embodiment of the invention in connection with the drawings.